Colonization of the human airways by Pseudomonas aeruginosa appears to be of paramount importance to the pathologic process which occurs in chronic lung diseases such as cystic fibrosis and bronchiectasis, since this organism does not invade beyond the lungs in these diseases. The site of colonization appears to be mucus or possibly mucus and cells. Thus, the long term objective of this work is to develop new approaches to the prevention of chronic Pseudomonas infections based on interference with bacterial colonization of the respiratory tract. In order to achieve this it will be necessary to understand the molecular basis of the interaction between Pseudomonas aeruginosa, and mucus. The specific aims of this proposal are therefore: (1) to identify and sequence the genes for two classes of nonpilus adhesins of P. aeruginosa which mediate adhesion to mucins; (2) to overexpress, purify and characterize these mucin adhesins; and (3) to identify the adhesive domains of these adhesins. To achieve these aims the mucin adhesin genes will be cloned from cosmids containing P. aeruginosa DNA which have been identified to contain the genes of interest. The proteins will then be overexpressed in E. coli using the T7 RNA polymerase system or others and purified by conventional means. The binding domains of the proteins will be mapped using two complimentary approaches. Nested deletions will be made from each end of the genes and the subsequent mutants and expressed proteins tested for adhesion to mucins in order to locate this domain. Additionally monoclonal antibodies will be raised against the adhesins and screened for their antiadhesive ability. Antiadhesive monoclonal antibodies will then be used to locate the binding epitopes on digests of the intact adhesins and on the truncated proteins. These studies will characterize and clarify the nature of the nonpilus adhesins for mucins, provide structural information, and will provide data to assess their feasibility as immunogens in an appropriate animal model.